The present invention relates generally to the field of underwater sound devices and, more specifically, to acoustic underwater sensor systems.
With the development of underwater launched cruise missiles, modern submarines are acquiring the ability to attack surface ships from increasingly long ranges. Thus, the defense of a surface battle group will require the ability to reliably detect and track submerged submarines within huge expanses of ocean at great distances from the ships.
Areas forward of a moving battle group present a particular problem. In these areas, an enemy submarine may come into a firing position without having to move at high speed, thus avoiding the resulting high emitted acoustic source levels associated with high speed travel.
The difficulties in detecting and tracking a submarine in a tactical situation could be eased by the availability of an appropriate passive acoustic search system. Hydrophone arrays used as the sensors should be ambient-noise limited, rather than self-noise limited, meaning that they should operate dead in the water. Furthermore, they should operate in locations where the ambient-noise field is not dominated by the battle group and, further, they should operate in locations nearer to ocean areas to be searched than to ships of the battle group. Thus, there exists a need for an acoustic underwater sensor system that can be air deployed and that is expendable. Prior to the present invention no such sensor system was believed to exist.